Normalization is used to decompose a larger, complex table into simple and smaller ones. This helps us in removing all the redundant data.
Generally, in a table, we will have a lot of redundant information which is not required, so it is better to divide this complex table into multiple smaller tables which contains only unique information.
First normal form:
A relation schema is in 1NF, if and only if :
– All attributes in the relation are atomic(indivisible value)
– And there are no repeating elements or group of elements.
Second normal form:
A relation is said to be in 2NF, if and only if:
It is in 1st Normal Form.
No partial dependency exists between non-key attributes and key attributes.
Third Normal form:
• A relation R is said to be in 3NF if and only if:
It is in 2NF.
No transitive dependency exists between non-key attributes and key attributes through another non-key attribute